An agent is an object in Creatures 3 and other games based on its engine, such as Docking Station, Creatures Adventures and Creatures Playground. They are comparable to COBs from Creatures and Creatures 2. They consist of a set of CAOS scripts and their dependencies (such as sprites and sound files). C3 and the other games mentioned consist almost entirely of agents, including the interface and the Creatures themselves.
If you like an agent, why not add it to the list of known agents?
Each agent is identified by a (usually) unique three-part number (classifier) consisting of a family, genus, and species. Each one is more specific than the last; for instance, family might indicate 'creature', genus 'grendel', and species 'male'.
CAOS scripts are associated with agents by these numbers. An agent's interactions in the world are characterised largely by its scripts: each classifier has particular event scripts attached to it, which fire when things happen to an agent using that classifier, and allow it to respond to the world.
A specific agent is also characterised by its internal state - this consists of many variables, among them various pieces of physics data and 100 generic agent variables (OVxx).
Files with the .agent or .agents extension contain an agent and its dependencies in a compressed format (PRAY). This is the usual method for distributing agents, as installing a single .agent file is much easier than moving many sprites and sounds to the correct folders. To install an .agent file, simply place it in the "My Agents" folder inside the main Creatures 3 or Docking Station folder. To inject an agent into any given world, use the Agent Injector screen in the Comms Room (in Docking Station), or the Agent Injector tool in the Engineering area (in Creatures 3). To uninstall an agent from any given world, each Agent Injector has an 'X' button (the C3 one is blue, the DS one is red) which can typically be used to remove the selected agent.
The process of .agent file creation can be summarised as follows:
- Create a COS file that contains the scripts and installation routine you desire
- Create a PRAY template text document. This is used by the PRAY Builder to construct an agent file.
- Place the PRAY Builder, COS and template file in the same folder ... along with any files needed by the agents (sprites, sounds, etc)
- Run PRAY Builder and after a short time you will have a .agent file that can be placed in the 'My Agents' folder of Creatures 3.
From the Creature Labs' Making Agents for Creatures 3 tutorial.